It's no secret that our nutrition directly impacts our health. The same is true when it comes to a pregnant woman’s nutrition and the health of her fetus. How exactly does a woman’s diet need to shift when she’s expecting though? Is she truly “eating for two?” Does she have to kiss coffee and alcohol goodbye until she delivers? We’ll walk through these points, I promise, but I want to give you a bit more background on evidence-based recommendations for nutrition during pregnancy.
If this topic interests you or is relevant to your situation, I’m sure an internet search has provided you with loads of conflicting recommendations as to what you should vs. should not eat or drink while pregnant. Some of these recommendations are evidence-based and some not so much…I don’t blame you for searching, pregnancy can be a wonderful yet stressful and confusing time! I just want to emphasize a few things before we dive some questions and answers:
1.) The amazing yet also frustrating thing about the internet is that you will find information that claims to support or refute any side of any issue.
2.) Not all information that claims to be true is based on evidence and research.
3.) One person’s experience while pregnant may not apply to your unique situation.
This next point is a big one that is not often shared yet is so important:
4.) The “answers” around nutrition during pregnancy aren’t always black and white, there’s a lot of grey. It’s difficult and often unethical to do clinical research trials (the gold standard of research) on pregnant women. Therefore, the best evidence we have to go off of often comes from observational studies. That means hard yes or no answers don’t exist for every question about nutrition during pregnancy.
Now that we’ve gone over some basics, let’s talk specifics! Here are a few common nutrition questions that surround pregnancy and the evidence-based answers to them!
Do I have to give up coffee, chocolate, and all other delicious forms of caffeine?
Short Answer: You do not have to give up caffeine but staying below 200 – 300 mg of caffeine per day is generally recommended (1).
Longer Answer + Evidence: The evidence we (the scientific community) have gathered through research has given us a range of caffeine intake during pregnancy that is thought to be safe/not cause adverse pregnancy outcomes. So why is there no hard and fast limit on caffeine? It’s challenging to research caffeine consumption and its impact on pregnancy! Study participants may struggle to accurately recall their caffeine intake, nausea can affect how much caffeine a woman consumes, among other challenges (1).
The American College of Obstetricians and Gynecologists states that less than 200 mg of caffeine a day does not appear to contribute to negative birth outcomes like miscarriages or preterm birth (2). However, A meta-analysis (giant scientific review of the data from multiple studies) found evidence to support consuming up to 300 mg of caffeine per day in a healthy pregnant woman (3). It’s also important to keep in mind that we all process caffeine a little differently (check out our previous blog on caffeine and stress for more information). Staying within 200-300 mg of caffeine a day generally looks like two to three 8 oz cups of coffee but remember caffeine is in more than just coffee (think chocolate, energy drinks, maybe even some supplements) (4).
Should I be eating for two?
Short Answer: You are eating to feed both yourself and your fetus but that does not mean double the calories. The general recommendation from the Institute of Medicine, for women at a healthy weight before pregnancy, is 0 additional calories in the 1st trimester, 340 additional calories in the 2nd trimester, and 452 additional calories in the 3rd trimester (5).
Longer Answer + Evidence: Calorie needs vary from person to person when a woman is not pregnant so the same is true when she is pregnant. The amount of energy you need to eat in a day is based on your metabolism, any health conditions you may have, how physically active you are, your age, etc. These variables still apply when a woman is pregnant.
On top of that, the number of calories you should be consuming during pregnancy also depends on how much weight you need to gain. Why does it matter how much weight you gain while pregnant? Well, too little and too much weight gain can both increase the risk for certain adverse pregnancy outcomes (6). The recommended amount of weight a woman should gain during pregnancy is based on her pre-pregnancy weight so it varies from person to person. Overall, your energy needs are unique to your situation and while you are technically eating for two, that second being is quite small and requires less energy than you do.
Is it dangerous to have any alcohol, at all, while I’m pregnant?
Short Answer: No safe level of alcohol consumption has been established through research so the recommendation is to abstain from any alcohol consumption during pregnancy (7).
Longer Answer + Evidence: Studying the impacts of alcohol intake on pregnancy is difficult: a clinical trial is unethical for obvious reasons, data can be impacted by women’s honesty in reporting alcohol consumption, different people process alcohol at different rates, and so on (7). Yet again we find ourselves in a situation where observational studies are the best evidence we have to go off of.
One systematic review looked at 46 different studies that researched the impacts of low to moderate alcohol consumption during pregnancy. The review specifically looked at several adverse outcomes, including how alcohol consumption may impact the risk of miscarriage, stillbirth, and growth restrictions. After taking a fine-tooth comb to these studies, there was inconclusive evidence that low to moderate alcohol consumption during pregnancy leads to adverse outcomes (8).
That being said, this is not necessarily a license to drink alcohol while pregnant. Just because there isn’t enough conclusive evidence to show that low to moderate alcohol consumption during pregnancy is unsafe doesn’t mean that it is safe to consume alcohol. We do know that alcohol is a teratogen (a substance that can cause abnormalities in a fetus) and can have negative effects on a baby (9). What we still don’t know is whether or not there is any level of alcohol consumption that is known to be safe during pregnancy.
You see what I mean when I say there is a lot of grey here?! This is where a registered dietitian comes in! It's the dietitian's job to review the data surrounding nutrition questions you may have during pregnancy and help put it into the context of your individualized health. I cannot emphasize enough that we all have our own unique nutritional needs, and this applies throughout pregnancy as well. A registered dietitian can work with you to determine what’s best for your individual needs, provide you with the truth as to what the risks and benefits are, and use shared decision making to determine the best path forward for a healthy pregnancy!
References:
1.) Vicki Nisenblat, R. J. N. (2020). The effects of caffeine in reproductive outcomes in women. Retrieved 10/26/2020, from UpToDate
2.) American College of Obstetricians and Gynecologists. ACOG CommitteeOpinion No. 462: Moderate caffeine consumption during pregnancy. Obstet Gynecol. 2010 Aug;116(2 Pt 1):467-8. doi: 10.1097/AOG.0b013e3181eeb2a1. PMID: 20664420.
3.) Wikoff D, Welsh BT, Henderson R, Brorby GP, Britt J, Myers E, Goldberger J, Lieberman HR, O'Brien C, Peck J, Tenenbein M, Weaver C, Harvey S, Urban J, Doepker C. Systematic review of the potential adverse effects of caffeine consumption in healthy adults, pregnant women, adolescents, and children. Food Chem Toxicol. 2017 Nov;109(Pt 1):585-648. doi: 10.1016/j.fct.2017.04.002. Epub 2017 Apr 21. PMID: 28438661.
4.) Staff MC. Caffeine Content for Coffee, Tea, Soda, and More. Mayo Clinic. https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/caffeine/art-20049372. Published 2020. Updated 02/29/2020. Accessed 07/24/2020, 2020.
5.) Institute of Medicine (US) and National Research Council (US) Committee to Reexamine IOM Pregnancy Weight Guidelines. Weight Gain During Pregnancy: Reexamining the Guidelines. Rasmussen KM, Yaktine AL, editors. Washington (DC): National Academies Press (US); 2009. PMID: 20669500.
6.) LifeCycle Project-Maternal Obesity and Childhood Outcomes Study Group. Association of Gestational Weight Gain With Adverse Maternal and Infant Outcomes. JAMA. 2019;321(17):1702–1715. doi:10.1001/jama.2019.3820
7.) Chang, G. (2020). Alcohol intake and pregnancy. Retrieved 10/26/2020, from UpToDate
8.) Henderson J, Gray R, Brocklehurst P. Systematic review of effects of low-moderate prenatal alcohol exposure on pregnancy outcome. BJOG. 2007 Mar;114(3):243-52. doi: 10.1111/j.1471-0528.2006.01163.x. Epub 2007 Jan 12. Erratum in: BJOG. 2007 Jul;114(7):914-5. PMID: 17233797.
9.) Akison LK, Moritz KM, Reid N. Adverse reproductive outcomes associated with fetal alcohol exposure: a systematic review. Reproduction. 2019 Apr 1;157(4):329-343. doi: 10.1530/REP-18-0607. PMID: 30653461.
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